HOUSES THAT HEAT AND COOL THEMSELVES – NATURALLY – EPISODE 1
This is what Kamermans Architects has successfully been designing for more than three decades. It is generally known as Passive Solar Design.
These houses are naturally comfortable, healthy, affordable and do not need any auxiliary heating or mechanical ventilation/cooling to meet minimum World Health Organisation thermal performance standards. It doesn’t need to cost more than conventional design and is fully compliant with the NZ Building Code (BC)
The four principles behind the Passive Solar Design are deceptively simple (refer attached diagram):
- 1 Optimum solar access: Put the windows in the right place; predominantly North, then East, then West and minimal on the South. The most obvious sun control is eaves but you only need them over northern glazing. No need for eaves around the whole house.
- 2 Thermal mass: (e.g. a concrete floor or walls). Provide thermal mass that acts as a ‘heatsink’ in winter and a ‘cool sink’ in summer. An (insulated) concrete floor slab is a logical choice. Most newly constructed houses in NZ sit on a concrete floor slab anyway. Make sure that most of the floor has a heat absorbent finish like polished concrete, natural stone, ceramic or porcelain tiles, all very common in Europe. Some strategically placed rugs will not reduce the thermal performance much.
- 3 Natural ventilation: Provide opening windows to each room allowing minimal secure cross ventilation all year round. Potential overheating is controlled by limited summer sun access to windows (e.g. with eaves) and ventilation outlets (windows or vents) at the high point of the house to create ‘stack’ ventilation.
- 4 Optimum insulation: The insulation helps keep the house warm in the winter and cool in the summer. Insulation being a low cost component of the overall construction cost, it pays to go beyond the minimum BC requirements. Double glazing is mandatory in most NZ regions. A cost effective way to enhance thermal performance is to install thermal drapes that are closed during evening and night.
The above four points can easily be achieved in NZ by simple low cost construction in accordance the NZ Building Code.
So what is the difference between Passive Solar Design and ‘standard’ construction?
The answer is intelligent design. The construction components (floors, walls, roofs, windows & doors etc.) do not need to cost more than ‘standard’ construction. The difference is in how they are put together in the overall design.
I hope the above will be useful to you, particularly if you are planning to invest in a new house. Feel free to contact me. I am happy to answer any questions you may have.